Can cold natural gas cause poor combustion? How is this compensated for?
I've been struggling to come up with a theory how the gas-air mix can become too rich, one is that it burns fine till the gas from the warm basement pipes is used up and it's getting denser cold gas from the street. I've looked at our hydronic boiler to see if it's flame is bad too, but can't see well through a 1/2" port without some disassembly. But what I can see is pretty yellow!
So how is this temp issue dealt with? Is there a mechanism either in the pressure drop regulator from the street or the meter that is supposed to regulate gas temp so the mixture stays consistent? If so, can it be faulty and causing the problem?
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its not the temperature of the gas as much as the temperature outside. You most likely have a supply problem. when it starts getting colder outside and everybody is using the gas for heat then the pressure is dropping and you are not getting the proper pressure to mix the air/gas mixture. you should request your gas company to come by and measure the gas pressure coming into the house.
also construction work outside can cause dirt and sediment to plug up supply piping coming into your house. check the flame on your water heater with the heating system off and then turn the heating system off and see if you notice the flame change. even the stove will change as the demand will increase.
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The gas pressure should be fairly constant, regardless of which appliance is operating. In residential settings we typically size the gas piping to have .03 inches of pressure drop (less than a one tenth of a pound pressure drop). Typically natural gas pressure to the house in my area is 6.0 inches of water column (roughly one quarter of a pound).
I would recommend you reach out to the utility company. Sounds like your meter or gas pressure regulator are acting up.1 -
My water heater is an indirect off the boiler, so that ain't gonna work! But low pressure or obstruction would lead to leaner mix not richer mix, as far as I can figure.pedmec said:its not the temperature of the gas as much as the temperature outside. You most likely have a supply problem. when it starts getting colder outside and everybody is using the gas for heat then the pressure is dropping and you are not getting the proper pressure to mix the air/gas mixture. you should request your gas company to come by and measure the gas pressure coming into the house.
also construction work outside can cause dirt and sediment to plug up supply piping coming into your house. check the flame on your water heater with the heating system off and then turn the heating system off and see if you notice the flame change. even the stove will change as the demand will increase.
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Shouldn't colder, denser gas burn richer? How does the delivery system compensate, is it part of the regulator?ScottSecor said:The gas pressure should be fairly constant, regardless of which appliance is operating. In residential settings we typically size the gas piping to have .03 inches of pressure drop (less than a one tenth of a pound pressure drop). Typically natural gas pressure to the house in my area is 6.0 inches of water column (roughly one quarter of a pound).
I would recommend you reach out to the utility company. Sounds like your meter or gas pressure regulator are acting up.0 -
Get someone there with a combustion analyzer and the training to use it.0
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@Jells
Call the gas company and ask them if they are "shaving" the gas.
It is very common in cold weather (which we just had) that the gas company in some areas will have problems maintaining the pressure in the gas mains due to high demand.
To compensate for this, they inject propane into the system to help keep the gas pressure up.
Google gas utilities shaving and you will find more information.
Systems provides turnkey engineering, project management and equipment supply for construction of LPG-air facilities used by gas-distribution utilities and industrial / commercial gas consumers of every size. LPG-air systems help reduce the overall cost of natural gas supply while enhancing supply security.
While propane-air peak shaving and standby systems are most common, LPG feedstocks with high butane content are also utilized. By mixing LPG with air, a fuel gas is created with burning characteristics matching available natural gas. Thus, LPG-air mixtures can substitute for some or all flowing gas-energy supply. LPG-air systems are also deployed as base-load systems prior to connection of natural gas in a developing area. Undiluted LPG is of course also widely used around the world. Standby provides a full range of LPG and natural gas products and technical services across the gas-energy spectrum.ep.
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@Jells
I've never seen any difference in my natural gas in 3 different towns. It looks and burns the same here at -8 as it does at 95f.
I'm not saying you're not seeing an issue as others mentioned they may be making up for demand by adding other fuels.
Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.
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Can you seeJells said:Get someone there with a combustion analyzer and the training to use it.
Like they grow on trees! Sore subject, long rant. But I don't need an analyzer to see the combustion is bad, licking yellow flame instead of nice blue tells me that! cold
Hot
CO
Oxygen
free air
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@ChrisJ
I only had issues once in Ma with Berkshire gas company which covers Pittsfield and the Berkshires.
We had 3 power burners in Pittsfield and all three were running fine with 0 issues all fall and into the winter. All 3 of these burners were on 3 different jobs and 3 different buildings miles apart from one another.
All of a sudden the weather turned cold and we started getting no heat calls on those 3 jobs.
All three burner were spark ignited gas pilots and the main burners were gas/oil. So the main burner could run gas or oil but with the same gas pilot burner.
We couldn't find any problem with any one of these burners, yet they were all locking out at random times. We ran them on gas and ran them on oil....still lockouts. Obviously, whatever the problem was it was common to both fuels.
The gas pilot was common to both fuels. Thes burner which were different makes and models all used 6000 volt ignition transformers. We swapped all 3 for 8500 volt transformers and never had another lock out.
After I talked with the gas company they admitted to shaving and adding propane to the system.
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One more thing about natural gas mains. In my area the mains are typically at least three feet below grade. Sometimes more like five or six feet below grade. I suspect the temperature of the natural gas is warmer than you suspect.
A
On the other hand, some homes have ten or twenty feet of exposed outdoor pipe. We have seen natural gas with high moisture levels. Occasionally a gas meter will slow or even stop flowing gas. Often this happens on bitter cold days.
Do you have a pressure regulator on the gas main?0 -
I'm in the city, no exterior gas pipe, comes underground from the street, and there's a regulator in the basement. This is also a multifamily house.ScottSecor said:One more thing about natural gas mains. In my area the mains are typically at least three feet below grade. Sometimes more like five or six feet below grade. I suspect the temperature of the natural gas is warmer than you suspect.
A
On the other hand, some homes have ten or twenty feet of exposed outdoor pipe. We have seen natural gas with high moisture levels. Occasionally a gas meter will slow or even stop flowing gas. Often this happens on bitter cold days.
Do you have a pressure regulator on the gas main?
@EBEBRATT-Ed: isn't mixing air, as in oxygen, into the feed incredibly dangerous? Now you can have an explosion INSIDE the pipeline!0 -
We have low pressure gas issues all over Boston. once the weather gets in the 10 degree range it starts to rear its ugly head. We have gas boosters all over the new construction in downtown Boston.
Yellow flames do not mean you are running "rich". it means you have incomplete combustion. Which can be caused by any number of issues. A low gas pressure at your equipment doesn't mean you have extra air in your combustion. it means there is not enough gas pressure to properly mix the O2 with the gas. Gas burners, whatever style or type are being used are engineered items. they are designed to mix the air/fuel ratio to get a clean burn.
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You need to run combustion analysis multiple times over a 20-30 min. period while monitoring the manifold gas pressure with all the rest of the house appliances off then repeat with everything under full load. Also, measure the surface temp of your burners from cold start to yellow-tipping. Classic yellow tipping is caused by low primary aeration with low manifold pressure.
Understand that as a burner heats up, the port loading changes. Also, the gas being discharged out the orifice into the burner mixer tube entrains primary air. At higher rates, more air gets drawn in. Also, denser gases, such as LP vs. NG draw in more air. If the air feed is subject to heating, yes, it can draw in less MakeUp Air as it warms. This is how a gas direct vent fireplace starts off with a clean, short, fake blue flame then stretches into a natural lazy yellow flame as the coaxial vent warms. If the air intake warms, it can reverse draft along its conduit surface against the flow of air thus reducing MUA.
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Ok. Obviously I don't have the expensive equipment! Do I call the utility or a gas heating tech? Seems like a appliance repair guy would have no idea of this stuff, at least in my experience with them.Bob Harper said:You need to run combustion analysis multiple times over a 20-30 min. period while monitoring the manifold gas pressure with all the rest of the house appliances off then repeat with everything under full load. Also, measure the surface temp of your burners from cold start to yellow-tipping. Classic yellow tipping is caused by low primary aeration with low manifold pressure.
Understand that as a burner heats up, the port loading changes. Also, the gas being discharged out the orifice into the burner mixer tube entrains primary air. At higher rates, more air gets drawn in. Also, denser gases, such as LP vs. NG draw in more air. If the air feed is subject to heating, yes, it can draw in less MakeUp Air as it warms. This is how a gas direct vent fireplace starts off with a clean, short, fake blue flame then stretches into a natural lazy yellow flame as the coaxial vent warms. If the air intake warms, it can reverse draft along its conduit surface against the flow of air thus reducing MUA.0 -
As mentioned earlier, I suggest you start with the gas company.0
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...then if you care, secure the equipment and information to find the problem, since you believe a qualified professional is unavailable.0
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Jells said:
Ok. Obviously I don't have the expensive equipment! Do I call the utility or a gas heating tech? Seems like an appliance repair guy would have no idea of this stuff, at least in my experience with them.
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@pedmec
About 10 years ago I did a gas booster in a grocery store in CT. In the process of getting quotes I spoke with a supplier in Boston (Maybe Eclipse) about a booster quote. The fellow mentioned that Boston was a great market for boosters due to the old gas pipe and low gas pressures.
He said at that time that they still had wooden gas pipe from the 1880 in service in Boston. This I found hard to believe. Do you know anything about this? Just for curiosity sake.0 -
Never heard of wooden gas but there are wooden water mains of that vintage in Hoboken. My street sewer is brick!EBEBRATT-Ed said:@pedmec
About 10 years ago I did a gas booster in a grocery store in CT. In the process of getting quotes I spoke with a supplier in Boston (Maybe Eclipse) about a booster quote. The fellow mentioned that Boston was a great market for boosters due to the old gas pipe and low gas pressures.
He said at that time that they still had wooden gas pipe from the 1880 in service in Boston. This I found hard to believe. Do you know anything about this? Just for curiosity sake.0 -
Do all the burners do it?Jells said:@Jells
Still yellow, and sometimes 'snaps' apparently because combustion is happening inside the burner.
What happens if you turn the burner down when it's doing that?Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.
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@EBEBRATT-Ed can't say i have. We have so many gas leaks that the number was at the absurd level. so many ibelieve they kind of stop talking about it. a lot of cities have changed to elevated pressure as they just replace everything.
Talked to a gas company executive a while back who told me when we have extreme cold weather they will shutdown the supply to the cape cod section of Massachusetts to ensure that the rest of the eastern seaboard supply is functional. I don't know what that temperature is but it's the only time ill be glad not to own a summer home there0 -
How is that relevant?CLamb said:Get someone there with a combustion analyzer and the training to use it.
I know on a furnace or boiler the combustion analyzer samples the gas from the flue exhaust. Seeing as how a stove burner isn't contained how does one sample it?
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How is that relevant?pecmsg said:
I know on a furnace or boiler the combustion analyzer samples the gas from the flue exhaust. Seeing as how a stove burner isn't contained how does one sample it?CLamb said:Get someone there with a combustion analyzer and the training to use it.
Well, if someone is trying to use a combustion analyzer on a stove burner then the combustion products must be sampled properly.0 -
If you say so.CLamb said:
Well, if someone is trying to use a combustion analyzer on a stove burner then the combustion products must be sampled properly.
How is that relevant?CLamb said:Get someone there with a combustion analyzer and the training to use it.
I know on a furnace or boiler the combustion analyzer samples the gas from the flue exhaust. Seeing as how a stove burner isn't contained how does one sample it?I’ve never used one on a stove!0
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